Flood Hazard

In Howard County, flood origins consist of riverine flooding from the tributaries of the Patuxent River bordering Prince George’s and Montgomery Counties to the southwest and the Patapsco River bordering Carroll and Baltimore County to the north and northeast. The rivers include the Little Patuxent River, the Middle Patuxent River, Cattail Creek, Deep Run, Dorsey Run, Bonnie Branch, Plumtree Branch, Guilford Branch, Hammond Branch, Clyde’s Branch, Tiber-Hudson Branch, and many others.

Howard County has had numerous incidents of flooding, including major events such as Tropical Storm Lee in 2011, Tropical Storm Agnes in 1972, Hurricane Eloise in 1975, and Hurricane Floyd in 1999. Most incidents are the result of tropical systems, nor’easters, and flash flooding from sudden, short-lived rainstorms. In 2010, Howard County developed a Flood Mitigation Plan (FMP) that outlines these flooding risks, preventative measures, and mitigation goals. See Howard County's FMP.

For more information on flood-related hazards in Howard County click on the links below:

Functions of the FloodPlain Areas

Floodplains are low land areas that are located next to rivers, streams, and lakes. Floodplains provide natural filtration of pollutants and provide breeding and feeding areas for wildlife. During increased rain and snow activity floodplains store rainwater, melted snowfall, and reduce flooding in surrounding areas. It is important to allow the floodplain to carry and store floodwaters in order to protect human life and property from flood damage and this is why Howard County does not allow building in the floodplain.

Floodplain Drainage System Maintenance

Dumping into our floodplains via the streams and rivers is a violation of Howard County Code Section 18.205 - Obstruction, damage and drainage and Section 18.502 - Prohibited discharges and illicit connections. Even grass clippings and branches that are dumped in the streams can accumulate and block the channels. When you expect a heavy rain or snow event, check that your local stormdrains are clear of debris. This will prevent water from backing up causing localized flooding. In Howard County, there are scattered areas that occasionally flood. They include, but are not limited to Main Street, Elkridge, and Allview Estates. Click on the link for roads that frequently flood in Howard County. Frequently Flooded Roads

Local Flood Warning System, Real Time Gauges, and NOAA Radios

During an emergency, the County's Public Information Office (PIO) sends out announcements to all television and radio stations that service the County, including WBAL and other local TV and radio stations. These announcements are then broadcast to residents. The County also has a Facebook page and Twitter account that residents can visit to get updates on emergency situations. For example, in September, the County offers tips on how to prepare for emergencies during National Preparedness Month. The County also operates a reverse 911 system, that allows the County to make phone calls to residents informing them of an impending emergency or evacuation. The County will provide residents with advanced warning which will vary based on the specific hazard that is being faced.

The County also maintains a local flood warning system. This system consists of several rain and stream level gauges located strategically throughout the County. The gauges measure the "stage" or the elevation of the water surface. The gauges are monitored during storms to determine whether significant flooding can be expected. If necessary, County residents who live in low lying flood prone areas will be alerted to possible flooding hazards. You can view the Howard County flood gauges data. To effectively use and compare the gauge data, a resident will need to know the elevation of their property. Surveyors can be hired to determine the elevation of a residential property. Here is a list of frequently flooded roads.

Residents should consider buying a National Oceanic and Atmospheric Administration (NOAA) weather radio that broadcasts continuous weather information on a frequency that is not heard on a regular radio. The NOAA radio can provide weather updates and keep you informed of weather hazards. More information about NOAA radios.

Map Information Service

The County provides residents with a map service using the FEMA Flood Insurance Rate Maps (FIRM), which show the locations of properties relative to the floodplain. Residents who want to know if they are located in or near the floodplain can call the Bureau of Environmental Services at 410-313-6444. You can also visit the County interactive map to access the County Geographic Information Systems and use the software to map your location to determine if you are in a flood area. Maps can also be found at your local County library.

Flood Protection Assistance

Howard County staff is available to speak, or meet with, residents about flood hazard, property protection, and/or possible financial assistance and make recommendations and/or referrals. The County can provide information on the County's restriction of no building in the floodplain and the steps to take to reduce the impact of flooding. For more information, please call the Bureau of Environmental Services at 410-313-6444.

As a public service, Howard County Government provides residents with the following floodplain information upon request based on the Federal Emergency Management Agency’s (FEMA’s) effective Flood Insurance Rate Map (FIRM):

Location and elevation of a property or building structure relative to the Special Flood Hazard Area (SFHA);

Information on the mandatory flood insurance purchase requirement for buildings that have federal or federally related loans or grants and are located in the SFHA;

Information on and copies of Elevation Certificates, Letters of Map Amendment (LOMA), Letters of Map Change (LOMC), and Letters of Map Revision (LOMR);

Information on historic FIRMs; and

Information on County-regulated floodplains and local drainage problems.

In order to obtain floodplain information, please check the Howard County Stormwater Management Division website, or you can contact the Stormwater Management Division by e-mail at DoIFlood@howardcountymd.gov. You may also visit or call the Stormwater Management Division office located in the Bureau of Environmental Services at 6751 Columbia Gateway Drive, Suite 514, Columbia, MD 21046, 410-313-6444 to obtain floodplain information and view paper copies of the FIRMs. Paper and digitized versions of the FIRMs may also be viewed at all Howard County libraries.

Flood Safety

Howard County provides flood safety and property protection information in the form of booklets and brochures, which can be obtained by calling the Bureau of Environmental Services at 410-313-6444. Here are a few things to watch out for:

If you live in an area subject to flooding, secure your property and be prepared for evacuation.

Do not walk through flowing water. Drowning is the number one cause of flood deaths, mostly from flash floods. Currents can be deceptive and 6 inches of moving water can knock you off your feet. If you walk in standing water, use a pole or stick.

Look before you step. After a flood, the ground and floor are covered with debris including broken bottles and nails. Floors and stairs that are covered with mud can be very slippery.

Do not drive through a flooded area. Most people drown in their cars than anywhere else during a flood.

Don't drive around road barriers; the road or bridge may be washed out.

Stay away from power lines and electrical wires. The number two flood killer after drowning is electrocution. Electrical currents can travel through water. Some appliances, such as television sets, keep electrical charges even after they have been unplugged. Don't use appliances or motors that have gotten wet unless they have bee taken apart, cleaned and dried.

Look before you step. After a flood, the ground and floor are covered with debris including broken bottles and nails. Floors and stairs that are covered with mud can be very slippery.

As water levels rise due to rain and ground saturation, flooding of basements and lower levels of homes and businesses is possible. Water can threaten utilities or the structural integrity of the home or building.

Be alert for gas leaks. Use a flashlight to inspect for damage. Don't smoke or use candles, lanterns, or open flames unless you know the gas has been turned off and the area has been ventilated.

Floodwaters can take hours or days to rise and can present a hazardous situation.

Emergency Planning

Floods and the damage they create can happen very quickly. It’s important to be prepared and have a plan beforehand that all members of your family will be familiar with and follow. Visit https://www.ready.gov/make-a-plan for guidelines on how to plan for an emergency.

In addition, a “Grab and Go” kit is an important part of how you respond to an emergency. You may want to keep one in your car and one in your home so that you’ll always have basic supplies with you when an emergency strikes. Visit https://www.ready.gov/kit for more information on what to put in a “Grab and Go” kit.

Flood Protection Measures

There are things you can do to minimize or eliminate property damage before a flood event. Properly grading your property, elevating and securing electrical appliances, using flood-resistant materials on exterior surfaces, and elevating or covering furniture and valuables are just a few ways to protect your property.

Buildings can also be permanently protected through “retrofitting”, which involves making changes to an existing building to protect it from flooding. There are six common retrofitting methods: Elevation - elevating the entire house so that the lowest floor is above the flood level; Wet Floodproofing – making uninhabitable portions of your house resistant to flood damage and allowing water to enter during flooding; Relocation - moving your house out of the floodplain to higher ground; Dry Floodproofing – sealing your home to prevent flood waters from entering; Levees and Floodwalls – building a floodwall or levee around your home to hold back flood waters; and Demolition – tearing down your damaged home and either rebuilding properly on the same property or buying or building a house elsewhere. You can also add a second story to the building, and use the bottom story for parking, access and storage. In an emergency, sandbags can be used to protect your property against flooding. For more information on floodproofing your home, order the Homeowner’s Guide to Retrofitting, Publication 312, by calling FEMA at 1-800-480-2520.

Wind and Hurricane Damage: High winds from hurricanes and storms can turn unsecured objects around your home into projectiles that can cause substantial damage. Garbage cans, sheds, garden furniture and other structures should be securely anchored with straps or ground anchors or if possible, placed indoors during high wind events. Anticipate tree damage by properly maintaining and trimming dead or dying trees.

Flood Insurance

Flood damage is not covered by homeowner's insurance policies, however, you can protect your home, business, and belongings with flood insurance from the National Flood Insurance Program (NFIP). You can buy flood insurance no matter what your flood risk, but don't wait for the next flood to buy insurance protection. There is usually a 30 day waiting period before the NFIP coverage takes effect. For information about the NFIP, call 1(800) 427-4661 or call your insurance agent for more information on rates and coverage. Residents who are interested in finding out more about how they can protect their homes against flooding can visit http://floodsmart.gov

Elevation Certificates

The County maintains a record of the elevation certificates for properties within the floodplain. To determine if your property has an elevation certificate on file with the County, call 410-313-6444 or check your property.

Floodplain Development Permit Requirements

Howard County does not permit development in the floodplain. Before you make any improvements (build on, alter, regrade, or fill in) on your property, please check with the Howard County Department of Inspections, Licenses, and Permits (DILP) located at 3430 Courthouse Drive, Ellicott City, MD 21043 (410) 313-2455 to determine if you are subject to building restrictions, if you see illegal development in the floodplain, or if the changes you make will alter water drainage and adversely affect other properties.

Substantial Improvements/Damage

Substantial Improvement: If a pre-FIRM building is remodeled, renovated, or improved and the project cost is 50% or more of the building value, the building will have to be brought into compliance with the NFIP standards. Project costs include structural costs, finished materials, built-in appliances, flooring, and interior finishes. The cost of permitting is not included.

Substantial Damage: If a building, which is located in a special hazard flood area, is damaged by any cause and the repair cost are 50% or more of the value of the building, the 50% Rule or Substantial Damage Rule applies and the building must be must be elevated and brought into compliance. The damage can be the result of wind, flood, fire, earthquake or man. This 50% Rule regulation applies to all structures in the designated special flood hazard area [100-Year Floodplain]. When evaluating a structure’s damage, only the building value, or market value of the structure is considered, while the underlying land and exterior improvements are excluded.